Aminocarboxylic acids and salts thereof



Patented June 11, 1935 UNITED sm AMINOCARBOXYLI O ACIDS AND SALTSTHEREOF Reinhold Fick, Ludwigshafenmany,

on-the-Rhine, Gerassignor to I. G. Farbenindustrie Aktiengesellschaft,Frankfort-on-the-Main, Germany N Drawing. Applica Serial No. 646,977. In1931 Claims.

The present invention relates to the production of aminocarboxylicacids, particularly alpha-aminocarboxylic acids, iminocarboxylic acidsand their salts.

5 The preparation of ammonia, as for example water, alcohols, ethers,pyridine or mixtures thereof.

The temperatures employed for the condensation should not exceed C. andare generally chosen between about 5 below zero centigrade and about 250., whereas temperatures between about C. are generallly aption December13, 1932, Germany December 31,

evaporation by working in if desired, introducing inert v the pressure.

the temperature of which is kept continually to 110 C. After all theam-' monia has been driven oil, a concentrated solution ofalpha-aminopropionic sodium salt containing only a slight amountoi othersubstances remains behind. The yield of alpha-aminopropionic sodium saltis about per cent of; the theoretical yield.

Example 2 A solution of alpha-aminopropionitrile is 'pre pared asdescribed in Example 1 and it is allowed to flow into a boiling solutionof v86 kilograms of barium hydroxide. monia has been driven off, thesolution of the barium salt is treated with the equivalent amount of awater-soluble sulphate, as for example sodium su1phate,- or acid,depending on whether itis desired to obtain a salt of thealpha-aminopropionic acid or the free acid itself, and the separatedfrom the precipitated barium sul- The yield of alpha-aminopropionic acidis about 85 per cent of the theoretical yield.

acid nitrile,

Emample a amount of other substances remains behind. Y

The yield of calcium iminodiacetate is about per cent of the theoreticalyield.

Example" 4 The crude aminonitrile solution obtained" according to.Example 3 is saponified by allowing it toflow into a boiling solution of86 kilograms of barium hydroxide. A solution which contains the bariumsalt of alpha-aminoacetic acid to the extent of about 75 per centisobtained.

Example 5 The crude aminonitrile solution obtained accordingto Example 1is saponified by allowing it to flow into a boiling solution of 56kilograms of potassium hydroxide in 200 kilograms of water. Afterdriving ofi the ammonia, a solution of the potassium salt ofalpha-amino-propionic acid is'obtained. The yield of the potassium saltof alpha-amino-propionic acid is more than per cent of the theoreticalyield.

Example 6 The crude aminonitrile solution obtained according to Example1 is saponified by allowing ity to flow into aboiling solution of 134kilograms of hydrated strontium hydroxide inv 160 kilograms of water. Inorder to obtain the free acid, the solution of strontiumalpha-aminopropionate thus obtained may be treated with an equivalentamount of sulphuric acid, the strontium sulphate being then removed byfiltration,

and. the filtrate evaporated to dryness. If instead of. sulphuric acid,a soluble sulphate, such assodiumsulphate or employed, the correspondingsalts are obtained after. filtration and alpha-aminopropionate ismorethan 85 per cent of the theoretical yield,

Whatl claim is t In the production of aminocarboxylic acids and saltsthereof by a condensation of an aldehyde with ammonium cyanide andsubsequent saponification of the'resulting aminocarboxylic the stepwhich comprises carrying out the said. condensation at a temperaturebehyde with ammonium sulphate, be

evaporation. The yield of tween about 5 below zero centigrade and about25 C. in the presence of a quantity of free ammonia corresponding atleast to that present in the combined state in said ammonium cyanide andsaponifying the aminocarboxylic acid nitrile in the resulting ammoniacalsolution with an alkali metal base.-

2.'In the production of aminocarboxylic acids and salts thereof by acondensation of an aldeammonium cyanide and subsequent saponification ofthe resulting aminocarboxylic acid nitrile, the step which comprisescarrying out the said condensation at a temperature between about 5below'zero centigrade and about 25 C. in the presence of a quantity offree ammonia corresponding at least to that present in the combinedstate in said ammonium cyanide, and saponifying the aminocarboxylic acidnitrile in the resulting ammoniacal solution with an alkali metal base,at a temperature between about 85 andabout C. while avoidingevaporation.

3. In the production of a-aminocarboxylic acids and salts thereof by acondensation of an aldehyde with ammonium cyanide and subsequentsaponification of the resulting aminocarboxylic acid nitrile, the stepwhich comprises carrying out the said condensation in the presence of aquantity of free ammonia corresponding at least to that present in thecombined state in said ammonium cyanide and saponifying theaminocarboxylic acid nitrile in the resulting ammoniacal solution withanaqueous alkali metal base. I

4. In the production of aminopropionic acid and salts thereof by acondensation of acetaldehyde with ammonium cyanide in the presence ofwater and subsequent saponification of the resulting aminocarboxylicacid nitrile, the step which comprises carrying out the saidcondensation at a temperature between about 5 below zero centigrade andabout 25 C. in the presence of a quantity of free ammonia correspondingat least to that present in the combined state in said ammonium cyanideand saponifying the a-amino propionic nitrile in the resultingammoniacal solution with an alkali metal base.

5. In the production of aminoacetic acid and salts thereof by acondensation of formaldehyde with ammonium cyanide in the presence ofwater and subsequent saponification of the resulting aminocarboxylicacid nitrile, the step which comprises carrying out the said condensation at a temperature between about 5 below zero C. and about 25 C. inthe presence of a quantity of free ammonia corresponding at least tothat present in the combined state in said ammonium cyanide andsaponifying the amino: acetic nitrile in the resulting ammoniacalsolution with an alkali metal base.

